computing Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, hardware and softw ...

, Direct Media Interface (DMI) is

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, and Delaware General Corporation Law, incorporated in Delaware. Intel designs, manufactures, and sells computer compo ...

's proprietary link between the northbridge (or

CPU A central processing unit (CPU), also called a central processor, main processor, or just processor, is the primary processor in a given computer. Its electronic circuitry executes instructions of a computer program, such as arithmetic, log ...

) and southbridge (e.g.

Platform Controller Hub The Platform Controller Hub (PCH) is a family of Intel's single-chip chipsets, first introduced in 2009. It is the successor to the Intel Hub Architecture, which used two chipsa northbridge and southbridge, and first appeared in the Intel 5 Se ...

family) chipset on a computer

motherboard A motherboard, also called a mainboard, a system board, a logic board, and informally a mobo (see #Nomenclature, "Nomenclature" section), is the main printed circuit board (PCB) in general-purpose computers and other expandable systems. It ho ...

. It was first used between the 9xx chipsets and the ICH6, released in 2004. Previous Intel chipsets had used the

Intel Hub Architecture Intel Hub Architecture (IHA), also known as Accelerated Hub Architecture (AHA) was Intel's architecture for the 8xx family of chipsets, starting in 1999 with the Intel 810. It uses a memory controller hub (MCH) that is connected to an I/O controll ...

to perform the same function, and server chipsets use a similar interface called ''Enterprise Southbridge Interface'' (ESI). While the "DMI" name dates back to ICH6, Intel mandates specific combinations of compatible devices, so the presence of a DMI does not guarantee by itself that a particular northbridge–southbridge combination is allowed. DMI is essentially

PCI Express PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe, is a high-speed standard used to connect hardware components inside computers. It is designed to replace older expansion bus standards such as Peripher ...

, using multiple lanes and

differential signaling Differential signalling is a method for electrically transmitting information using two complementary signals. The technique sends the same electrical signal as a differential pair of signals, each in its own conductor. The pair of conduc ...

to form a point-to-point link. Most implementations use a ×8 or ×4 link, while some mobile systems (e.g. 915GMS, 945GMS/GSE/GU and the

Atom Atoms are the basic particles of the chemical elements. An atom consists of a atomic nucleus, nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished fr ...

N450) use a ×2 link, halving the bandwidth. The original implementation provides 10 Gbit/s (1 GB/s) in each direction using a ×4 link. The DMI provides support for concurrent traffic and isochronous data transfer capabilities. DMI replaced FSB (

Front-Side Bus The front-side bus (FSB) is a computer communication interface ( bus) that was often used in Intel-chip-based computers during the 1990s and 2000s. The EV6 bus served the same function for competing AMD CPUs. Both typically carry data between th ...

) which was eliminated in 2009.

Versions

DMI 1.0, introduced in 2004 with a data transfer rate of 1 GB/s with a ×4 link. DMI 2.0, introduced in 2011, doubles the data transfer rate to 2 GB/s with a ×4 link. It is used to link an Intel

with the Intel

(PCH), which supersedes the historic implementation of a separate northbridge and southbridge. DMI 3.0, released in August 2015, allows the 8 GT/s transfer rate per lane, for a total of four lanes and 3.93 GB/s for the CPU–PCH link. It is used by two-chip variants of the Intel

Skylake Skylake or Sky Lake may refer to: * Skylake (microarchitecture) Skylake is Intel's codename for its sixth generation Core microprocessor family that was launched on August 5, 2015, succeeding the Broadwell microarchitecture. Skylake is a mic ...

microprocessors, which are used in conjunction with

Intel 100 Series chipsets This article provides a list of motherboard chipsets made by Intel, divided into three main categories: those that use the PCI bus for interconnection (the 4xx series), those that connect using specialized "hub links" (the 8xx series), and those ...

; some low power (Skylake-U onwards) and ultra low power (Skylake-Y onwards) mobile Intel processors have the PCH integrated into the physical package as a separate die, referred to as OPI (On Package DMI interconnect Interface) and effectively following the

system on a chip A system on a chip (SoC) is an integrated circuit that combines most or all key components of a computer or Electronics, electronic system onto a single microchip. Typically, an SoC includes a central processing unit (CPU) with computer memory, ...

(SoC) design layout. On 9 March 2015, Intel announced the Broadwell-based Xeon D as its first enterprise platform to fully incorporate the PCH in an SoC configuration. In 2021, with the release of 500 series chipsets, Intel increased the amount of DMI 3.0 lanes from four to eight, doubling the bandwidth. DMI 4.0, released on November 4, 2021 with 600 series chipsets, doubles the bandwidth each lane provides and is two times faster when compared to DMI 3.0. The number of DMI 4.0 lanes depends on chipset model used.

Implementations

2005 Centrino mobile platform. At the time DMI linked the GMCH and

I/O Controller Hub I/O Controller Hub (ICH) is a family of Intel Corporation, Intel southbridge (computing), southbridge microchips used to manage I/O, data communications between a CPU and a motherboard, specifically Intel chipsets based on the Intel Hub Architectur ...

. Northbridge devices supporting a northbridge DMI are the Intel 915-series, 925-series, 945-series, 955-series, 965-series, 975-series, G31/33, P35, X38, X48, P45 and X58. Processors supporting a northbridge DMI and, therefore, not using a separate northbridge, are the

Intel Atom Intel Atom is a line of IA-32 and x86-64 instruction set ultra-low-voltage processors by Intel Corporation designed to reduce electric consumption and power dissipation in comparison with ordinary processors of the Intel Core series. Atom is m ...

Intel Core i3 Intel Core is a line of multi-core (with the exception of Core Solo and Core 2 Solo) central processing units (CPUs) for midrange, embedded, workstation, high-end and enthusiast computer markets marketed by Intel Corporation. These processors ...

Intel Core i5 Intel Core is a line of multi-core (with the exception of Core Solo and Core 2 Solo) central processing units (CPUs) for midrange, embedded, workstation, high-end and enthusiast computer markets marketed by Intel Corporation. These processors ...

, and

Intel Core i7 Intel Core is a line of multi-core (with the exception of Core Solo and Core 2 Solo) central processing units (CPUs) for midrange, embedded, workstation, high-end and enthusiast computer markets marketed by Intel Corporation. These processors ...

(8xx, 7xx and 6xx, but not 9xx). Processors supporting a northbridge DMI 2.0 and, therefore not using a separate northbridge, are the 2000, 3000, 4000, and 5000 series of the

, Core i5 and Core i7. Southbridge devices supporting a southbridge DMI are the ICH6, ICH7, ICH8, ICH9, ICH10, NM10, P55, H55, H57, Q57, PM55, HM55, HM57, QM57 and QS57. PCH devices supporting DMI 2.0 are the Intel B65, H61, H67, P67, Q65, Q67, Z68, HM65, HM67, QM67, QS67, B75, H77, Q75, Q77, Z75, Z77, X79, HM75, HM76, HM77, QM77, QS77, UM77, H81, B85, Q85, Q87, H87, Z87, H97, Z97, C222, C224, C226,

X99 Intel X99, List of Intel codenames, codenamed "Wellsburg", is a Platform Controller Hub (PCH) designed and manufactured by Intel, targeted at the Desktop computer, high-end desktop (HEDT) and enthusiast segments of the Intel product lineup. Th ...

, H110, and H310. PCH devices supporting DMI 3.0 are the Intel Z170, H170, HM170, Q170, QM170, Q150, B150, C236, CM236, C232, and C620. The Intel 200 series, B360, H370, Q370, Z370, Z390, C246, and Intel 400 series chipsets also support DMI 3.0. PCH devices supporting DMI 4.0 are the Intel 600 and 700 Series chipsets.

References

{{Computer bus, state=collapsed Intel products Computer buses Serial buses

Versions

Implementations

See also

References